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description: Learn about the high availability design of OpenBao.
---

# High availability

OpenBao can run in a high availability (HA) mode to protect against outages by running multiple OpenBao servers.


# Design overview

The primary design goal for making OpenBao Highly Available (HA) is to
minimize downtime without affecting horizontal scalability. OpenBao is
bound by the IO limits of the storage backend rather than the compute
requirements. Being bound by the IO limits simplifies the HA approach and avoids complex
coordination.

Storage backends, such as Integrated Storage, provide additional coordinative
functions enabling OpenBao to run in an HA configuration. Supported
by the backend, OpenBao will automatically run in HA mode without further
configuration.

When running in HA mode, OpenBao servers have two states they
can be: **standby** and **active**. For multiple OpenBao servers sharing a storage
backend, only a single instance is active at any time. All standby instances are placed in hot standbys.

Only the active server processes all requests; the standby server redirects all requests to an active OpenBao server.

Meanwhile, if the active server is sealed, fails, or loses network connectivity,
then one of the standby OpenBao server becomes the active instance.

Please note that only _unsealed_ OpenBao servers may act as a standby.
If a server is in a sealed state, it cannot act as a standby. Servers in a sealed state cannot
 serve any requests if the active server fails.
